Metal extrusion press with die-assembly locking means



Dec. 12, 1967 SNELL ETAL 3,357,226

METAL EXTRUSION PRESS WITH DI EASSEMBLY LOCKING MEANS Filed March 12,1965 IN V E N TORS DONALD NOEL SNELL ROBERT KENNETH VALKS I m EATTORNEYS United States Patent 3,357,226 METAL EXTRUSION PRESS WITHDIE-ASSEMBLY LOCG MEANS Donald N. Snell and Robert Kenneth Vallrs,Dorset, England, assignors to The Loewy Engineering Company Limited,Bournemouth, England, a company-of Great Britain Filed Mar. 12, 1965,Ser. No. 439,256 Claims priority, application Great Britain, Mar. 19,1964, 11,701/64 8 Claims. (Cl. 72-253) ABSTRACT OF THE DISCLOSUREDescribes a metal extrusion press with means to hold the die carrierstationary, when the billet container is moved away from the die at theend of an extrusion, for the purpose of severing the discard from theextrusion.

In most metal extrusion presses, the billet-container and thedie-assembly can be moved apart from each other in the axis of the pressso as to provide a gap between them in which, after the extrusion of abillet, a shear or saw can be entered for the purpose of severing theextruded product from the billet residue.

After an extrusion, this residue remains in the container bore andadheres firmly to it, so that upon separation of the billet-containerand die-assembly, the extruded article, while still connected to theresidue, seeks to pull the dieassembly along. This pull can beconsiderable, particularly in the case of presses using port-hole dies.

In modern extrusion presses, the die-assembly is frequently mounted on acarrier in the form of a wheel or arm rotatable about an axis parallelto and spaced at some distance from the press axis. Presses of this typehave a high output and other important advantages. In such presses, thedie-assembly is supported in the press frame at a point at some distancefrom the axis of the press. Hence, when a pull is exerted on the dieassembly in the direction of this axis, as is the case upon retractionof the container before the separation of the residue, it is inevitablethat the die-assembly and the wheel or rotary arm mounting the assemblyare subjected to a bending moment. This is undesirable.

It has been proposed to provide in a metal extrusion press in which thedie-assembly is mounted on a rotary arm, movable means which, when inposition, lock the die-assembly against pull in the direction of thepress axis, and thereby eliminate bending moments due to that pull.

According to one proposal, these locking means comprise a slide whichcan be moved towards and away from the press axis and which, when movedtowards this axis, engages the rotary arm of the die-assembly from theside. This proposal leads to a somewhat bulky and heavy design which,especially in view of the somewhat congested con- 'ditions in the regionnear the die-assembly, is undesirable. Moreover, the locking of thedie-assembly can only take place at one side thereof, and may lead,especially in the case of heavy pulls, to canting of the die-assembly,with the result that excessive pressure may occur at the points ofengagement between the die-assembly and the slide.

It is therefore an object of the present invention to provide a metalextrusion press with locking means for the die-assembly which is freefrom these disadvantages, and which, at the same time, provides apositive retaining hold on the die-assembly against any pull transmittedto it by the extruded article from the container upon its retractionbefore the severance of thebillet residue.

An embodiment of the invention is described by way of example withreference to the accompanying drawings, in which:

FIG. 1 is a transverse section through a metal extrusion press accordingto the invention along the line I-I of FIG. 2.

FIG. 2 is a longitudinal section of a part of the extrusion press alongthe line IIII of FIG. 1.

FIG. 3 is a fragmentary view of parts of FIG. 2 on a larger scale.

The press illustrated in the drawings comprises a stationary platen 2secured to a main cylinder (not shown) by columns 4, and abillet-container 6 in a containercarrier 8. The container is adapted toco-oper-ate, for the extrusion of a billet, with one of two dies 10, thelatter being both mounted in a common carrier 12 rotatable about a shaft14. The axis of this shaft is laterally spacedapart from the main axisof the press, as seen in FIG. 1.

Each of the two dies belongs to a separate die-assembly; such anassembly comprises, in addition to die 10, a back ing ring 16 locatedimmediately behind the die and mounted in the carrier 12, as well asbolsters 18 and 20 which are interposed between the carrier 12 and theplaten 2. The bolster 18 may be removably secured to another bolster 20or may be located in a slide, not shown, guided on the platen 2 or on arotary arm. The diametrically opposite ends of the carrier 12 are shapedas twopronged forks (FIG. 1) and a die 10, together wit-h backing ring16 of its assembly, is entered from the side between the prongs 21 ofthe carrier.

The mounting of the die-assemblies on a common rotary carrier makes itpossible to place one die-assembly in the main axis of the press andbetween platen 2 and container 6, and the other assembly at the sametime at an outside or parking station for exchange or reconditioning ofits components. The die-assemblies exchange their respective positionsby rotation of the carrier 12 about shaft 14.

A plate 22 is secured by strong bolts 24 to the platen 2, the platehaving lugs 26- projecting from it towards the container 6. The bolts 24are shown in FIG. 2 as passing through the entire length of the platenand being secured at the outside of the platen by nuts. Two pairs oflugs are provided on the plate 22 in the embodiment shown and thesepairs are arranged as shown in FIG. 1 diametrically opposite each otherand symmetrically with respect to the main press axis. Secured in holesin the lugs 26 of each pair is a pin 28 on which latches 30 are rockablymounted. The pins extend at right-angles to a plane passing through thepress axis, so that the latches 30 move in that plane when rocked aboutthe pins 28. Pivot-ably mounted on the platen 2 at 31 arepiston-and-cylinder units 32, one for each lug 30, the piston rods beingattached at 34 to the latches.

The ends of the latches are formed as hooks 36 which are adapted, asshown in FIG. 2 and more particularly in FIG. 3, to enter into recessesat the container side of the carrier 12 and thus engage from behindshoulders 38 on that carrier. As shown in FIG. 1, the shoulders 38 areformed on the prongs 21.

If an extrusion operation is to be carried out, a billet is placed inthe bore of the container 6, and a die-assem-bly with its die 10 ispositioned in the press axis, as shown in FIG. 1. Pressure is thenapplied to the billet by a pressing stem, not shown, whereupon thebillet is extruded through the die 11 as is well-known, and thus forms aproduct which leaves the press through a tunnel it? in the platen 2.After extrusion of the billet has been completed, the pressing stem iswithdrawn from the container 6. As well-known in extrusion practice, acertain residual amount of the billet cannot be extruded and remains inthe container bore adhering firmly to the wall of that bore. Thisresidue must be severed from the extruded product before the latter canbe withdrawn from the press. To this end, the container 6 is retractedfrom the die-assembly, by means not shown, in, order to make it possiblefor a cutting device to pass through the extruded article at a pointbetween the container and the die. During the retraction of thecontainer at this stage, the extruded product is anchored to thecontainer by the residue adhering to the wall of the container bore. Onthe other hand, the product also fitstightly in the dieaperture, so thatupon retraction of the container, at strong pull in the direction ofthecontainer movement is exerted on the die-assembly through the extrudedproduct. In presses fitted with port-hole dies, the area of contactbetween die and extruded product is considerably greater than with opendies, and therefore the tendency of the die-assembly to follow thecontainer during the latters movement is the more pronounced. The pullexerted by the product acts in the press axis and produces therefore abending moment on the die-assembly and the carrier 12, since the latteris supported on shaft 14 whose axis is spaced-apart from the press axis.

In the press according to the invention, this pull is counteracted bythe latches 30 which, when in their effective position, engage withtheir books 36 the shoulders 38 of the carrier 12 from behind. The pullon the carrier 12 is thus resisted through the latches 30 which, asdescribed before, are anchored to the platen 2 through the bolts 24, theplate 22 and the lugs 26.

. After retraction of the container 6 from the die-assembly, a length ofthe extruded product extending between container and die is laid openand a gap is also formed between container and die through which a saw59 can move and sever the extruded product from the residue in thecontainer bore. The extruded product can then be removed from the pressthrough the tunnel 40.

In some cases, it is desired to sever the residue from the extrudedproduct at a point between the die 19 and the bolster 18. In this event,the latches 30 are locked about their pivots 28 into the positions shownin chain lines in FIG. 3, so that the hooks 36 are disengaged from theshoulder 38. Carrier 12, together with the die-assemblies, can now bemoved, by means not shown, in the same axial direction as the container,so that a gap will be formed between the die 10 and the bolster 18 forthe entry thereinto of the saw 50 which, of course, must be axiallymovable.

The die-assembly locking means provided in accordance with the inventionmay have means for resisting downward thrust on the carrier 12. Such athrust is, for instance, exerted by a shear 41 (FIG. 2) which isusedinstead of a saw-for cutting the billet residue from the extrudedproduct at the face of the die. The means for resisting downward thrustconsist here of tongues 42 formed on the lugs 26, which tongues enterinto recesses 44 in carrier 12. (FIG. 3). In this case, the carrier 12has to be moved axially away from the platen 2 so as to disengage thetongues 42 before the carrier can be rotated.

Prior to the use of the shear 41, the container 6 is retracted from thedie-assembly as described before, but the pressing stem is left in theadvanced position so that the billet residue is forced out of thecontainer bore upon retraction of the container. The shear 41 is thenlowered from the position in FIG. 2 and cuts along the face of die 10,thus severing the residue adhering to that face from the extrudedproduct.

The invention is capable of embodiments other than those shown anddescribed with reference to the accompanying drawings. The number oflatches 30 and their distribution around the press axis may be altered,but the latches should preferably be spaced at equal distances from eachother and symmetrically around and with respect to a plane passingthrough the press axis. Instead of pivotally mounting thepiston-and-cylinder units 32 on the platen 2, these units may be fixedon the platen and articulated links be provided between the units andthe pivots 34. The latches 34, instead of being pivoted to the platen 2may be pivoted to the carrier 12. and co-operate with their hooked endswith shoulders on the platen or a partsecured to it.

The main feature of the invention is seen in the provision of aplurality of latches symmetrically disposed around and with respect to aplane passing through the press axis and adapted to anchor to the platenof an extrusion press a carrier for die-assemblies, which carrier issupported on an axis spaced-apart from the press axis.

We claim:

1. A metal extrusion press, having a stationary platen, a billetcontainer, movable along the press axis, and a carrier for adie-assembly, said carrier being arranged between platen and containerand supported for rotation about an axis parallel to the press axis, andin which retractable :means are provided for holding said carrieragainst movement along the press axis in the direction of saidcontainer, said means comprising a plurality of retractable latchesmounted on pivots and symmetrically disposed around and with respect toa plane passing through the press axis and engaging said carrier atpoints on the container side of said carrier.

2. A metal extrusion press according to claim 1, in which said latchesare formed at their ends with hooks disposed between said platen andsaid carrier, said hooks being pivoted to one of the two last-mentionedparts and adapted to be moved in locking engagement with the other part.

3. A metal extrusion press according to claim 1, in which the latchesare pivoted to lugs projecting from the platen.

4-. A metal extrusion press according to claim 3, in which the lugs arearranged on a separate plate secured to the platen by bolts passingthrough the platen.

5. A metal extrusion press according to claim 2 in which the hooks onthe latches are adapted to enter behind shoulders formed on the carrier.

6. A metal extrusion pres-s according to claim 1, in which cylinderunits are mounted on the platen for rock ingthe latches about theirpivots.

7. A metal extrusion press according to claim 1, in which the latcheshave means for resisting downward thrust on the die-assembly carrier.

8. A metal extrusion press according to claim 7, in which the meansprovided on the latches for resisting downward thrust consist of tonguesformed on the lugs in which the latches are pivotally mounted.

References Cited UNITED STATES PATENTS 2,757,794 8/1956 Walgren 72-263 X3,147,863 9/1964- Rosenthal 72-255 FOREIGN PATENTS 944,251 12/1963 GreatBritain. CHARLES W. LANHAM, Primary Examiner,

K. C. DECKER, Examiner.

1. A METAL EXTRUSION PRESS, HAVING A STATIONARY PLATEN, A BILLETCONTAINER, MOVABLE ALONG THE PRESS AXIS, AND A CARRIER FOR ADIE-ASSEMBLY, SAID CARRIER BEING ARRANGED BETWEEN PLATEN AND CONTAINERAND SUPPORTED FOR ROTATION ABOUT AN AXIS PARALLEL TO THE PRESS AXIS, ANDIN WHICH RETRACTABLE MEANS ARE PROVIDED FOR HOLDING SAID CARRIER AGAINSTMOVEMENT ALONG THE PRESS AXIS IN THE DIRECTION OF SAID CONTAINER, SAIDMEANS COMPRISING A PLURALITY OF RETRACTABLE LATCHES MOUNTED ON PIVOTSAND SYMMETRICALLY DISPOSED AROUND AND WITH RESPECT TO A PLANE PASSING